A steel plate is used for interior and exterior parts of an automobile, such as a body, a front door, a rear door, a back door, a front bumper, a rear bumper, and a rocker molding of an automobile in a related art. From the viewpoint of weight reduction in an automobile, partial use of a crystallizable thermoplastic resin such as a polypropylene resin is increased.
In a case of using a resin for interior and exterior parts of an automobile as described above, a primer composition is usually applied to an adhesion face of a resin member and an adhesive is then applied followed by adhering.
To eliminate a step of applying a primer composition, a method in which an adhesion face of a resin member is subjected to a dry treatment such as a flame treatment, a corona treatment, a plasma treatment, and ITRO treatment, in advance and a predetermined adhesive is applied directly to the adhesion face followed by adhering, to produce an adhesion member (multilayer member) has been also proposed (for example, Japan Unexamined Patent Publication No. 2014-25000).
Recently, the level of requirement for an automobile, such as safety and fuel consumption, has increased. Further improvement is required for the adhesion of a multilayer member (adhesion between adhered members).
When the present inventors produced a multilayer member using a member subjected to a dry treatment and an adhesive with reference to Japan Unexamined Patent Publication No. 2014-25000, they found that the adhesion of the multilayer member is not necessarily sufficient.